clark



E. W. CLARK.

BENCH DRILL.

APPLICATION FILED AUG.28. 191s.

Patented Nov. 25, 1919.

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APPLICATION FILED AUG.28. 191s.

Patented Nov. 25, 1919.

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BENCH DRILL.

APPLICATION FILED AUG. 2B. 1918 3 SHEETS-SHEET 3.

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ERNEST W. CLARK, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE SIGOURNEY TOOL COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT.

BEN CH-DRILL.

- Application filed August 28, 1918.

To all whom it may concern.-

Be it known that I, ERNEST WV. CLARK, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in Bench-Drills, of which the following is a specification.

This invention relates to the driving mech anism of those machine tools which are commonly known as bench drill presses.

In driving a small drill at very high speeds, especially for accurately drilling hard steel, it is essential that the support be firm and the driving means he so arranged that the rotations of the drill be uniform and steady. To obtain the necessary speed with driving means that occupies but little space it is desirable to employ a horizontal counter-shaft between a horizontal driveshaft and the vertical drill-spindle and to belt a pulley on the drive-shaft to a pulley on the counter-shaft and belt a pulley on the counter-shaft to a pulley on the drillspindle.

The object of this invention is to provide a simple, cheap and firmly supported driving means for high speed machines of this type, having two belts, one between drillspindle and counter-shaft and the other between drive-shaft and counter-shaft with the counter-shaft and drive-shaft so mount ed that the exact necessary alinement and tension of the two belts may be readily ob tained and easily retained to insure steady running, efficient action and accuracy of cutting of the drill at high speeds.

Figure 1 of the accompanying drawings shows a side elevation of a bench drill which has a driving means arranged according to this invention. Fig. 2 shows a rear elevation of the same. Fig. 3 shows a plan. Fig. 1 is a horizontal section taken on the 1plane indicated by the dotted line 4.4 on

The machine shown has a column 2 rising from a base 1. At the upper end of the column is the fixed head 3 and below the fixed head is the adjustable head. 4, these heads supporting the vertical drill-spindle 5 in the usual manner. Splined on the drill-spindle or attached to a sleeve splined on the drill- 1spinlle in the common way, is a small pul- Adjustably mounted on the base back of the column'is a yoke-shaped frame 7 having Specification of Letters Patent.

Patented Nov. 25', 1919.

Serial No. 251,718.

upright arms which support the horizontal drive-shaft 8. This yoke is held to the top of the base by screws 9 that have washers 10 above their heads, and that after passing through slots 11 in the base, screw into the bottom of the yoke. The bottom of the yoke at the back edge has an upstanding threaded lug 12 turning in which is the end of a screw 13 that is supported by a lug 14 extending up from the back edge of the base. The screw has a head 15 by means of which it maybe turned. On the underside of the yoke is a tongue 16 which fits in a slot 17 for guiding the yoke in its forward and backward movements. On the front edge of the lowerpart of the yoke a lever 18, provided with a belt shifting fork 19, is pivoted. By turning the handle of the screw this yoke-shaped frame, which carries the drive-shaft and the belt-shifter, may be moved, at any time that it is desired, toward and from the front and back of the machine.

On the drive-shaft at one side is a loose pulley 20 and adjacent thereto a fixed pulley 21. On the drive-shaft back of the supporting column is a three-step cone pulley 22.

At the top of the supporting column and extending upwardly and backwardly therefrom is a bracket 23. Adjustably mounted on this bracket is a yoke-shaped frame 24:. This yoke is held in place by screws 25 that pass through slots 26 in the yoke and screw into the top of the bracket. Supported by a lug 27 extending upwardly from the front edge of the bracket is a screw 28 which is threaded-into the front edge of the yoke.

This screw is provided with ahead 29 which, when turned, moves the upper yoke-shaped frame toward the front or toward the rear of the machine, depending upon the direction in which it is turned.

A counter-shaft 30 is supported horizontally by bearings in the rear ends of the upper adjustable yoke. Keyed on this counter-shaft above and in the plane of the cone pulley 22 on the drive-shaft, is a cone pulley 31. Also keyed on this counter-shaft is a pulley 32. The pulley 32 on the horizontal counter-shaft carried by the upper adjustable yoke is connected to the pulley 6 on the vertical drill-spindle by a belt 33, and the pulley 3 1 on the counter-shaft is connected by a belt 34 with the pulley 22 on the drive-shaft carried by the lower adjustable the bracket for adjusting yoke. By turning the screw head 29 the counter-shaft yoke may be adjusted so as to tighten the belt from the counter-shaft to the drill-spindle to just the desired degree. This also to an extent tightens the belt from the counter-shaft to the drive-shaft, but should this latter belt be insufliciently tightened or should it be too tight its tension may be made proper by turning the screw head 15 and adjusting the drive-shaft yoke.

The invention claimed is;

1. The combination with a base and column of a drill press ofa yoke-shaped frame adjustably mounted on the base back of the column, means on the base for adjusting said base yoke forwardly or rearwardly, a drive shaft supported horizontally by said base yoke, pulleys on the drive shaft, a bracket extending upwardly and rearwardly from the column, a yoke-shaped frame adjustably mounted on said bracket, means on said bracket yoke forwardly and rearwardly, a counter-shaft supported horizontally by said bracket yoke, pulleys on the counter-shaft, and a belt conrecting a pulley on the drive shaft and a pulley on the counter-shaft.

2. The combination with the base and column of a drill press of a yoke-shaped frame adjustably mounted on the base back of the column, means on the base for adjusting said base yoke forwardly or rearwardly, a drive shaft supported horizontally by said base yoke, pulleys on the drive shaft belt shifting means mounted on the adjustable base yoke, a bracket extending upwardly and rearwardly from the column, a yoke-shaped frame adjustably mounted on said bracket, means on the bracket for adjusting said bracket yoke forwardlyand rearwardly, a counter-shaft supported horizontally by said bracket yoke, pulleys on the counter-shaft, and a belt connecting a pulley on the drive shaft and a pulley on the counter-shaft ERNEST W. CLARK. 

